Materials Data on Hg3AsSe4Br by Materials Project
Hg3AsSe4Br crystallizes in the hexagonal P6_3mc space group. The structure is two-dimensional and consists of two Hg3AsSe4Br sheets oriented in the (0, 0, 1) direction. Hg2+ is bonded to three Se2- and one Br1- atom to form a mixture of edge and corner-sharing HgSe3Br trigonal pyramids. There are one shorter (2.62 Å) and two longer (2.70 Å) Hg–Se bond lengths. The Hg–Br bond length is 3.05 Å. As3+ is bonded in a distorted T-shaped geometry to three equivalent Se2- atoms. All As–Se bond lengths are 2.44 Å. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 3-coordinate geometry to two equivalent Hg2+ and one As3+ atom. In the second Se2- site, Se2- is bonded in a 3-coordinate geometry to three equivalent Hg2+ atoms. Br1- is bonded in a 3-coordinate geometry to three equivalent Hg2+ atoms.